1. Field of the Invention
This invention relates to an electronic apparatus such as a book-sized personal computer or word processor and, more particularly, it relates to a base unit to be used for such an electronic apparatus comprising a battery pack for storing a drive power source and a keyboard.
2. Description of the Related Art
Various book-sized or so-called lap-top personal computers comprising a flat and box-shaped base unit and a keyboard and a flat panel-type display unit arranged on said base unit are currently available.
Computers of the above described type are normally provided with a rechargeable battery pack for storing a drive power source so that they may be used at locations where the commercial power supply is not available. Since such a battery pack needs to be replaced by a new one when the battery pack contained there has lost its life after a long use, it is normally removably fitted to the base unit. In other words, the base unit of a conventional computer of the type under consideration is provided with a storage space for containing a battery pack. Such a storage space is located adjacent to and in communication with a loading port disposed on a lateral side of the base unit, through which the battery pack is pushed into and taken out of the storage space.
The loading port is normally closed by a cover. The cover is fitted to the base unit in such a manner that it is slidable between a closed position for closing the loading port and an open position for exposing the aperture. When the cover is in the closed position, its outer surface is found on the plane of the outer surface of the lateral side wall of the base unit on which the loading port is located to form a continuous plane so that the cover constitutes part of the side wall.
The base unit contains in it functional components such as printed-circuit board carrying various circuit components thereon and floppy disc drive device. So, the base unit is normally divided into two sections; an upper case and a lower case. In the base unit comprising the upper case and the lower case, the loading port extends from a lateral side of the upper case to the corresponding lateral side of the lower case and the cover for closing and exposing the port is slidable between the upper case and the lower case.
The walls of both the upper case and the lower case are made very thin to maximize the inner spaces of the cases sometimes at the cost of the rigidity of the top wall of the upper case and the bottom wall of the lower case having a relatively large surface area. Since the top wall of the upper case is used to support a display unit which is hinged to the upper case, any force applied to the display unit to open or close it is transmitted to the top wall of the upper case, which then can be deflected because of the lack of sufficient rigidity. Additionally, since the battery pack normally weighs more than one kilogram, the bottom wall of the lower case can also be deflected when the battery pack is loaded in the storage area of the lower case.
A base unit having deflected walls of the upper and lower cases can significantly lose its esthetic and hence commercial value. Besides, the loading port can vary its vertical dimension depending on the deflection of the top and bottom walls of the upper and lower cases, resulting in malfunctions such as a totally removed cover or an unmovable cover.